The two words hurdle and obstacle are co-related to each other, but, a hurdle is a barrier which has to be passed, while an obstacle is a block inbetween the task.

They are commonly used words to express obstructions. Obstacles are a block providing obstructions, while hindrance provides obstructions to delay.

The words obstacle and impediment are types of hindrances. Obstacle means obstruction barrier in progress, while impediment means obstruction barrier in any task.

The comma and period are distinguished with reference to their functions. Comma is used to connect the elements, whereas period is used to end the sentence.

The basic difference between a comma and a full-stop is that a comma does not end a statement, whereas, a full-stop is used to end the statement.